* Note that this fine latitudinal resolution is not the resolution of the underlying spatial information and only provided as a smooth, yet mean-preserving interpolation of the 15-degree latitudinal files to assist modelling groups in implementing the 15-degree files in their atmospheric grids.

DATA FORMAT:

The data is made available netcdf, CSV (files 2-4), XLS, and Matlab .mat (R2016a) files.The datapoints are given as area-averages for the centre of each equal-latitude bin, hemisphere or the global domain. The monthly values are given as time-averages for that respective month or year.

RECOMMENDED USE:If possible, please prescribe the (gridded) surface concentration fields with monthly and latitudinal resolution for the concentration-driven historical CMIP6 runs. Alternatively, modelling groups can choose to only presribe hemispheric or even global means. Note however, that a bias of too little forcing in the Northern hemisphere might be introduced, if globally uniform concentrations of CO2 and CH4 were assumed. Please document clearly your choice.

The provided datasets are surface concentrations. it is assumed that modelling groups have their own capabilities to propagate those concentrationsvertically throughout the troposphere and stratosphere. Options for a default vertical extension are provided in the Meinshauen et al. manuscript., GMD

KNOWN ISSUES:

26 July 2016: The annual netcdf files’ time axis is offset by one year. That error seems to be affecting all mole_fraction_of_XXX_in_air_input4MIPs_GHGConcentrations_CMIP_UoM-CMIP-1-1-0_gr3-GMNHSH_0000-2014.nc files. The time axis in corresponding csv, mat and xls files seems to be correct (same name, ending with .csv, .mat and .xlsx, respectively). The correct annual data time axis starts in year 0 and ends in year 2014 (not 2015). Thanks to Olivier Boucher for spotting that.

PERIOD OF RECORD: Data available from 0 (1 BC) to Year 2014, inclusive.The period to be used for the historical CMIP6 run is 1850 to 2014.

THANKFUL ACKNOLWEDGEMENT:This data is composed from a large number of station data andicecore records. The contributions the respective measurement initiativesand data compilers (especially NOAA ESRL and AGAGE networks) did, is greatfully acknowledged and this product would not have been possible without those vital datasets. The full list of references is going be included in time for the final data release.

CONTACT:Please contact Malte Meinshausen, Climate & Energy College,The University of Melbourne, Victoria, Australia.malte.meinshausen@unimelb.edu.auwith any suggestions or bug reports in regard to the data, format, or description.Please feel free to do so by phone (Australian time): +61 390356760 Thank you.